mego818: how much will a pr3 10 year old site go for?

The value of a site depends on the content and what the current market is. The true value of a site, or anything for that matter, is what someone is willing to pay for it. I suggest browsing popular marketplaces and comparing your site against others that are similar to get a feel for what you might be able to expect.

That depends on your website niche

yes, it depend on the keyword of the domain and niche too.

every website depends on the niche, so an exact answer can't be gived.

It depends on a lot of things besides those numbers. You could get $20 for it or you could get $20,000. 

What site is it?